Microsurfacing has recently been accepted widely as an effective method for preventive maintenance of pavements.Microsurfacing is a mixture of cationic polymer-modified bitumen emulsion,100%manufactured well-graded fi...Microsurfacing has recently been accepted widely as an effective method for preventive maintenance of pavements.Microsurfacing is a mixture of cationic polymer-modified bitumen emulsion,100%manufactured well-graded fine aggregate,mineral filler,water,and chemical additives.In this research,in order to evaluate the performance of steel slag in microsurfacing mixture,two types of bitumen emulsions(cationic quick setting and cationic slow setting)were used together with three types of mixtures in which 100%siliceous aggregate was used as a control mixture and then steel slag was replaced by 61%and 100%aggregate of control mixture.The performance of the samples was evaluated by experiments included wet cohesion test,wet track abrasion test,and loaded wheel test,according to international slurry surfacing association(ISSA)A143 guideline and ASTM D6372 standard.The results of tests showed that steel slag aggregate has proper compatibility with both of bitumen emulsion types judged by its desirable physical,chemical,and mechanical properties.The alkali characteristic of the steel slag leads to a stronger adhesion of these materials to acidic bitumen and cause prevented the stripping in the vicinity of water in comparison to the control mixture.Also,steel slag-containing mixtures displayed a more appropriate behavior in terms of rutting and stripping distresses.展开更多
The article presents Polish experience with cold recycling of asphalt pavements with the usage of bituminous emulsion and cement. In the 1990 s numerous roads in Poland required immediate reinforcement due to their si...The article presents Polish experience with cold recycling of asphalt pavements with the usage of bituminous emulsion and cement. In the 1990 s numerous roads in Poland required immediate reinforcement due to their significant degradation. Implementation of the cold recycling technology was one of the solutions to this problem. Cold recycled mixtures contain e beside the recycled asphalt pavement and aggregate e two different types of binding agents: bituminous emulsion and Portland cement. First Polish requirements were developed in the 1990 s and were based on the Marshall test. After several years of application of these requirements, numerous transverse cracks appeared on the pavements. Field investigation showed that the frequency of transverse cracking was not uniform on all evaluated sections and that the growth rate of the number of cracks was decreasing. The main reason of extensive cracking was the overly high amount of the Portland cement and insufficient amount of the bituminous emulsion. This led to production of very stiff mixtures, with dominance of hydraulic bonds, which behaved similarly to cement-treated mixtures. The idea of flexible cold recycled base course was not utilized. This experience motivated the Polish Road Administration to develop new requirements. Second part of the article presents the new requirements for cold recycling.New test methods as well as requirements concerning resistance to frost and water action were introduced in 2013. Implementing of the new requirements resulted in significant reduction in stiffness of the MCE mixtures. Values of stiffness modulus are even three times lower, which should significantly decrease the amount of potential reflective cracks on the pavement surface. Presently two types of technology of cold recycling are used in Poland, in-place and in-plant.展开更多
文摘Microsurfacing has recently been accepted widely as an effective method for preventive maintenance of pavements.Microsurfacing is a mixture of cationic polymer-modified bitumen emulsion,100%manufactured well-graded fine aggregate,mineral filler,water,and chemical additives.In this research,in order to evaluate the performance of steel slag in microsurfacing mixture,two types of bitumen emulsions(cationic quick setting and cationic slow setting)were used together with three types of mixtures in which 100%siliceous aggregate was used as a control mixture and then steel slag was replaced by 61%and 100%aggregate of control mixture.The performance of the samples was evaluated by experiments included wet cohesion test,wet track abrasion test,and loaded wheel test,according to international slurry surfacing association(ISSA)A143 guideline and ASTM D6372 standard.The results of tests showed that steel slag aggregate has proper compatibility with both of bitumen emulsion types judged by its desirable physical,chemical,and mechanical properties.The alkali characteristic of the steel slag leads to a stronger adhesion of these materials to acidic bitumen and cause prevented the stripping in the vicinity of water in comparison to the control mixture.Also,steel slag-containing mixtures displayed a more appropriate behavior in terms of rutting and stripping distresses.
基金supported by the project RID-1A (DZP/ RID-I-06/1/NCBR/2016) financed by the National Center for Research and Development and the General Directorate for National Roads and Motorways under the program “Development of Road Innovations”
文摘The article presents Polish experience with cold recycling of asphalt pavements with the usage of bituminous emulsion and cement. In the 1990 s numerous roads in Poland required immediate reinforcement due to their significant degradation. Implementation of the cold recycling technology was one of the solutions to this problem. Cold recycled mixtures contain e beside the recycled asphalt pavement and aggregate e two different types of binding agents: bituminous emulsion and Portland cement. First Polish requirements were developed in the 1990 s and were based on the Marshall test. After several years of application of these requirements, numerous transverse cracks appeared on the pavements. Field investigation showed that the frequency of transverse cracking was not uniform on all evaluated sections and that the growth rate of the number of cracks was decreasing. The main reason of extensive cracking was the overly high amount of the Portland cement and insufficient amount of the bituminous emulsion. This led to production of very stiff mixtures, with dominance of hydraulic bonds, which behaved similarly to cement-treated mixtures. The idea of flexible cold recycled base course was not utilized. This experience motivated the Polish Road Administration to develop new requirements. Second part of the article presents the new requirements for cold recycling.New test methods as well as requirements concerning resistance to frost and water action were introduced in 2013. Implementing of the new requirements resulted in significant reduction in stiffness of the MCE mixtures. Values of stiffness modulus are even three times lower, which should significantly decrease the amount of potential reflective cracks on the pavement surface. Presently two types of technology of cold recycling are used in Poland, in-place and in-plant.
